If this were on a unix system I'd say to check the permissions of the file it's trying to open. But since it's on windows I remember a similar characteristic when you open the explorer menue. If you right click on a file and select properties under the general tab it says the file attributes, It will say Archive, Read Only, Hidden, And System. I'd check those properties and see if it's checked as an archive so it's accessible.

It opens the file just fine, it even generates the .c source code file...then it gives me the couldn't open error. I checked and made sure the file was "Archived," it was. Perhaps "Couldn't Open !" refers to the compiler that is suppose to compile the .c source file (which is being generated).